Placental fusion is a phenomenon that can occur in a twin pregnancy. This can occur to varying degrees. Determination of chorionicity on ultrasound can sometimes be difficult if there has been a placental fusion.
In a DCDA pregnancy, there are no vascular anastomoses between the twin placentae and with an equator marking a zone of disc fusion where there is a narrow band at the equator where chorionic vessels do not cross 4.
In a MCDA pregnancy, multiple vascular anastomoses are usually present making the junction less distinct with examples of arterial to venous, arterial to arterial, or venous to venous connections being evident 4.
- 1. Baergen RN, Benirschke K. Manual of Pathology of the Human Placenta. Springer Verlag. (2010) ISBN:1441974938. Read it at Google Books - Find it at Amazon
- 2. Baldwin VJ. Pathology of multiple pregnancy. Springer. (1994) ISBN:0387940111. Read it at Google Books - Find it at Amazon
- 3. Faye-Petersen OM, Heller DS, Joshi VV. Handbook of placental pathology. Informa Healthcare. (2006) ISBN:1842142321. Read it at Google Books - Find it at Amazon
- 4. Histopathological examination of the placenta in twin pregnancies. (2018) APMIS. 126 (7): 626. doi:10.1111/apm.12829 - Pubmed